import 'package:flutter/material.dart';

void main() {
  runApp(const MyApp());
}

class MyApp extends StatelessWidget {
  const MyApp({Key? key}) : super(key: key);

  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: const MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  const MyHomePage({Key? key, required this.title}) : super(key: key);

  final String title;

  @override
  State<MyHomePage> createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage>
    with SingleTickerProviderStateMixin {
  late AnimationController _controller;

  @override
  Widget build(BuildContext context) {
    Animation animation1 = Tween(begin: 0.0, end: 1.0)
        .chain(CurveTween(curve: Interval(0.0, 0.2)))
        .animate(_controller);

    Animation animation2 = Tween(begin: 0.0, end: 1.0)
        .chain(CurveTween(curve: Interval(0.0, 0.2)))
        .animate(_controller);

    Animation animation3 = Tween(begin: 1.0, end: 0.0)
        .chain(CurveTween(curve: Interval(0.4, 0.95)))
        .animate(_controller);
    return Scaffold(
      appBar: AppBar(
        title: Text(widget.title),
      ),
      body: Center(
        child: AnimatedBuilder(
          animation: _controller,
          builder: (BuildContext context, Widget? child) {
            return Container(
              width: 300,
              height: 300,
              decoration: BoxDecoration(
                shape: BoxShape.circle,
                color: Colors.blue,
                gradient: RadialGradient(
                    colors: [
                      Color.fromARGB(255, 30, 138, 233),
                      Color.fromARGB(255, 184, 219, 248)
                    ],
                    stops: _controller.value < 0.2
                        ? [animation1.value, animation1.value + 0.1]
                        : [animation3.value, animation3.value + 0.1]),
              ),
            );
          },
        ),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: () {
          _controller.stop();
        },
        tooltip: 'Increment',
        child: const Icon(Icons.add),
      ), // This trailing comma makes auto-formatting nicer for build methods.
    );
  }

  @override
  void initState() {
    super.initState();
    _controller = AnimationController(
      duration: const Duration(seconds: 4),
      vsync: this,
    )..repeat(reverse: true);
    // _controller.addListener(() {
    //   print("${_controller.value}");
    // });
  }

  @override
  void dispose() {
    _controller.dispose();
  }
}
